Plot up to 6 functions and see roots, vertex, asymptotes, increasing and decreasing intervals and intersections marked on the graph and explained next to it. Zoom, a, b and c sliders, PNG and SVG export.
Type y = f(x) and the graph appears instantly, with zoom, panning and the value of f(x) under the cursor. The difference is in the properties. For polynomial and rational functions the tool uses exact algebra. For a linear function f(x) = ax + b the root is -b/a. For a quadratic ax² + bx + c the discriminant is Δ = b² - 4ac, the roots are (-b ± √Δ)/2a and the vertex sits at x = -b/2a and y = -Δ/4a. In a rational function such as (2x + 1)/(x - 3), the vertical asymptote is the root of the denominator (x = 3) and the horizontal one comes from the ratio of the leading coefficients when the degrees are equal (y = 2). If the numerator also vanishes at the root of the denominator, as in (x² - 1)/(x - 1), there is no asymptote but a hole at the point (1, 2). For exponentials, logarithms, trigonometric functions and absolute values, roots, extrema, inflection points and asymptotes are estimated numerically over the region shown, with the derivative computed symbolically whenever possible, and the panel makes clear what is exact and what is an estimate. Plotting is adaptive: it refines where the curve bends and breaks the line at poles and jumps, so the tangent never gets fake vertical lines. Everything runs in your browser and no function is sent to a server.
Paste the code into your HTML and the tool shows up on your page, without J-Kit's navigation and ads. It still runs in the browser of whoever visits your site.
<iframe
src="https://jkit.tools/embed/en-US/function-grapher"
width="100%"
height="600"
style="border:0"
loading="lazy"
title="Online Function Grapher"
></iframe>These references help contextualize formulas, standards, APIs and limitations used on this page. They do not replace professional validation when a result has legal, financial, medical or operational impact.
Type the function, for example x^2 - 4x + 3. The parabola opens upward if a is positive and downward if it is negative. The vertex is at x = -b/2a: here x = 2 and y = -1. The roots come from (-b ± √Δ)/2a with Δ = b² - 4ac = 4, so x = 1 and x = 3, and the parabola crosses the y axis at c = 3. The tool marks all of these points and shows their exact form.
Quadratic function, f(x) = ax² + bx + c with a not equal to 0. The graph is a parabola, symmetric about the vertical line through the vertex. Here a = 1, b = -4 and c = 3; the parabola opens upward.
Exact result (algebra)
Linear function, f(x) = ax + b. The graph is a line: a is the slope (increasing if a is positive) and b is where the line crosses the y axis. Here a = 0.5 (increasing) and b = 1.
Exact result (algebra)
| x | f₁(x) | f₂(x) |
|---|---|---|
| -5 | 48 | -1.5 |
| -4 | 35 | -1 |
| -3 | 24 | -0.5 |
| -2 | 15 | 0 |
| -1 | 8 | 0.5 |
| 0 | 3 | 1 |
| 1 | 0 | 1.5 |
| 2 | -1 | 2 |
| 3 | 0 | 2.5 |
| 4 | 3 | 3 |
| 5 | 8 | 3.5 |